Subcellular regulation of glucose metabolism through multienzyme glucosome assemblies by EGF-ERK1/2 signaling pathways

A multienzyme metabolic assembly for human glucose metabolism, namely the glucosome, has been previously demonstrated to partition glucose flux between glycolysis and building block biosynthesis in an assembly size-dependent manner. Among three different sizes of glucosome assem-blies, we have shown that large-sized glucosomes are func-tionally associated with the promotion of serine biosynthesis in the presence of epidermal growth factor (EGF). However, due to multifunctional roles of EGF in signaling pathways, it is unclear which EGF-mediated signaling pathways promote these large glucosome assemblies in cancer cells. In this study, we used Luminex multiplexing assays and high-content single-cell imaging to demonstrate that EGF triggers temporal acti-vation of extracellular signal-regulated kinases 1/2 (ERK1/2) in Hs578T cells. Subsequently, we found that treatments with a pharmacological inhibitor of ERK1/2, SCH772984, or short-hairpin RNAs targeting ERK1/2 promote the dissociation of large-sized assemblies to medium-sized assemblies in Hs578T cells. In addition, our Western blot analyses revealed that EGF treatment does not increase the expression levels of enzymes that are involved in both glucose metabolism and serine biosynthesis. The observed spatial transition of glucosome as-semblies between large and medium sizes appears to be mediated by the degree of dynamic partitioning of glucosome enzymes without changing their expression levels. Collectively, our study demonstrates that EGF-ERK1/2 signaling pathways play an important role in the upregulation of large-sized glu-cosomes in cancer cells, thus functionally governing the pro-motion of glycolysis-derived serine biosynthesis.

Automated summary

This study demonstrated that EGF triggers temporal activation of ERK1/2 in Hs578T cells, and inhibition of ERK1/2 promotes the dissociation of large-sized assemblies to medium-sized assemblies. The transition of glucosome assemblies between large and medium sizes is mediated by dynamic partitioning of enzymes without changing their expression levels.